For many of the military personnel being honored this Veteran's Day, the terror of war didn't end when they came back home. Some 30 percent of the men and women who have spent time in war zones experience symptoms of a debilitating condition called post-traumatic stress disorder (PTSD).

"Although PTSD was first brought to public attention by war veterans, it can result from many kinds of traumatic incidents," said Ellen Gerrity, Ph.D., associate director of research on aggression and trauma at the National Institute of Mental Health (NIMH). "Millions of other Americans who have experienced natural and human-caused disasters, child or spouse abuse, rape, or other dangerous crimes, as well as people who witness such trauma to a loved one, also suffer from this condition."

Research sponsored by NIMH and the Department of Veterans Affairs (VA) shows that PTSD affects several body systems including the central nervous system; it causes changes in brain chemicals and possibly in brain structures. "These discoveries, which are giving us a better understanding of the disorder, have led to improved treatments-or even prevention of symptoms in some cases," said Gerrity. More than 4 percent of the U.S. population, or at least 5.7 million people, experience PTSD in a given year.

People with PTSD often feel emotionally numb and detached from others. They may be easily startled, subject to unexpected outbursts, and depressed. Many have nightmares or trouble sleeping, difficulty concentrating, and some suffer from panic attacks or chronic anxiety. At any time, the trauma may come flooding back in the form of flashbacks. Often, PTSD symptoms can hamper the ability to hold down a job or feel pleasure from normal relationships with family and friends.

"The development of PTSD may be linked to the way in which the brain ties the emotions generated during the traumatic event to the memory of the event," said Matthew Friedman, M.D., Ph.D., executive director of the VA National Center for PTSD. "For most people, memories of fearful traumatic events diminish over time. But for people with PTSD, the events they experience are so overwhelming that they continue to suffer from high levels of fear and anxiety, even though the original stimuli are no longer present."

Flashbacks, which can happen many times each day and are one of the major symptoms of PTSD, are not a "remembering" of the traumatic experience, but a "reliving" of it, said Friedman. The mind of the person experiencing a flashback is essentially transported in time and place to the traumatic event.

Scientists at both the VA and NIMH are working to understand what brain changes are associated with flashbacks and other symptoms of the disorder such as numbing and being easily startled. They are also exploring whether the brain and other physiological changes associated with PTSD can be reversed through treatment.

Treatments developed through research help many people with PTSD deal effectively with their symptoms. Studies show that people can improve with cognitive-behavioral therapy, group therapy, or exposure therapy. Support from family and friends can also be an important part of recovery. For example, a large study of Vietnam veterans found that soldiers who had good social support after they returned home were less likely to develop PTSD.

"There is also a great deal of current research on medications for PTSD with some very promising preliminary results," said Terence Keane, Ph.D., director of behavioral science at the National Center for PTSD.

Researchers don't know why some people who suffer traumatic events go on to develop PTSD and others do not, but recent NIMH- and VA-funded research may help doctors better identify people who may be more prone to developing the disorder. People with PTSD tend to have abnormal levels of key hormones involved in response to stress. Cortisol levels are lower than normal and epinephrine and norepinephrine are higher than normal. Scientists have also found that people with this condition have alterations in the function of the thyroid and in neurotransmitter activity involving serotonin and opiates.

Animal investigations show that the hippocampus-a part of the brain critical to memory and emotion-appears to be smaller in cases of PTSD. NIMH and the VA are conducting brain imaging studies to see if the same is true in humans and, if so, whether it is related to short-term memory problems.

NIMH is conducting a national education program on anxiety disorders, which include PTSD, panic disorder, obsessive-compulsive disorder, phobias, and generalized anxiety disorder. For more information about PTSD and other anxiety disorders, see the Web site for the National Institute of Mental Health (NIMH) at http://www.nimh.nih.gov/anxiety or call 1-88-88-ANXIETY for a free packet of information. This site is hotlinked to the Web site for the National Center for Post-Traumatic Stress Disorder of the Department of Veterans Affairs at http://www.dartmouth.edu/dms/ptsd.

To interview Drs. Gerrity, Friedman, or Keane, contact the people listed on the first page or the Office of Scientific Information at 301-443-4536.

The National Institute of Mental Health is a component of the National Institutes of Health (NIH), the Government's primary agency for biomedical and behavioral research. NIH is part of the U.S. Department of Health and Human Services. The U.S. Department of Veterans operates nationwide programs of health care, assistance services, and national cemeteries for the nation's 26 million veterans. The National Center for PTSD is funded by the VA to provide international leadership in research, education, and clinical care for people with PTSD.